Electrical power generation devices use power inputs including, but not limited to electromagnetic waves (sunlight, infrared light, etc.), thermal energy, mechanical energy and nuclear energy and then convert these different forms of energy inputs into useable electrical power. The manufacture of these devices, although well established, can still be expensive and complicated.
Most power generation today occurs from the irreversible combustion of fossil fuels and although this form of energy conversion is still less expensive than other types of electricity generation, the long term damage to the environment and human health is not currently born by the cost of energy production. In addition, the conversion of petroleum to electrical energy is estimated to be only 9% efficient.
The cost of electricity produced from solar cells is still quite expensive when compared to fossil fuel based electrical power generation, and there remains the problem of energy storage in the absence of relevant light frequencies (night time). In addition, because of the photoelectric effect, solar cells can take advantage of only certain frequencies of sunlight, rendering their efficiency at around 11-30% of incident energy from the sun.
Other types of energy conversion systems based on wind, hydroelectric, and nuclear energy input, while cost effective in some cases, still negatively impact the environment and/or may require large capital outlays. Other more exotic types of electrical generation devices such as thermoelectric, thermionic and magneto-hydrodynamic ones do not currently have the conversion efficiencies necessary to make them adaptable to mass electrical power production and in addition, are complicated to manufacture. Even with the current price of oil as of Oct. 2, 2006 hovering at $61/barrel, alternative forms of energy conversion are still not cost effective to produce and operate. Those forms of energy input (for example, coal and nuclear) that are considered cost competitive with petroleum-based energy inputs create damage to the environment through the emission of greenhouse gases and particulates or through the production of radioactive waste.